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    SubjectLinux slowdown on 20M - summary
    Hi!

    [I'm now connected via cslip on 2400 modem, so sorry for bad formating/
    typos]

    I recently posted results of some tests - consisting of compilation of
    2.1.35 kernel on 2.1.35 linux. Everything on 486DX2/80 with
    20MB of ram.

    On 20MB of ram, it took 32 minutes (128k l2 enabled)
    on 16MB of ram (or with mem=16M option) it took
    22 minutes (with l2 cache enabled).

    Everyone told me that it is HW problem because my high 4MB of ram
    are not cacheable.
    So I turned level 2 cache off completely.

    COmpile time with mem=16M was 30 minutes,
    with 20MB of ram it was 35 minutes.

    So problem still exists with l2 disabled.

    [It still may be hw, however]

    Other think I noticed is that time from Uncompressing kernel to Elf:login differs heavily (15 sec X 25 sec) with 16MB and 20MB
    of memory (16MB is faster). Also 'interactive performance' is much
    worse with 20MB.
    Both even if l2 disabled.


    Other ideas (beside of cache problems were:)

    Problems with disk access not possible to memory higher that 16MB directly -
    impossible since I do not use DMA on disks and since disk activity when
    compiling kernel is almost none.
    David (?) Told me something about inode cache.

    Pavel


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